Routing Protocols

Routing protocols are designed to collect data on interconnection topologies. The main task of routing, or, in other words, the selection of the most optimal route, is usually solved by analyzing the special tables that are located in all the end network nodes and routers.

In order to automatically build the required tables, the routers change with each other certain information using specially designed service protocols, they are called "routing protocols". These include the protocols NLSP, RIP, OSPF, which need to be distinguished from network, for example, such as IP.

With the help of appropriate protocols, routers are gradually forming a network connection map. Already on the basis of this data, it is decided for each of the network numbers which specific router to transmit packets that are sent to this network so that the route eventually turns out to be the most rational. The results of the decisions taken are recorded in the routing table. When network configurations change, some records automatically become invalid. Then packets that are sent on false routes can get lost or go in cycles. From how quickly routing protocols lead the contents of the table to the actual position in the network, the quality of the work depends directly.

Routing protocols have several classifications. They can be either single-step or multi-step, static, dynamic, class, classless. In addition, such protocols can be external and internal. In the one-step selection of the most rational route, only the short-range router is initially defined, and not all of their sequence. Static routes are entered manually by the network administrator . Usually they are used in small networks, which differ in a simple and understandable structure. Plus, of course, is the ease of configuration, the absence of any traffic loss to transmit information about routing and low requirements for resources. But if there are changes in the network configuration, you have to manually change the routing table on all hosts. However, the protocols of dynamic routing are very popular.

The BGP protocol is one of the main routing protocols on the Internet. It is intended for the exchange of data on routes between large autonomous systems, therefore, in addition to standard information, transfers route data to autonomous systems. The BGP protocol selects the best route based on the rules that are accepted in the network, and does not use technical metrics in its work. Also, this protocol uses summation of routes in order to reduce routing tables. At the moment there is the fourth version of the protocol.

OSPF is also a fairly popular dynamic protocol. It is based on a technology that monitors the state of the channel and uses the Dijkstra algorithm for its work . Its advantages include high speed convergence, the most efficient use of bandwidth and support for network masks of variable length.

RIP-protocol - one of the oldest, which, however, is widely distributed to this day. It is used in small networks with a simple structure. The protocol is easy to operate and install. At the heart of his work lie algorithms of the vector of distances. When using RIP, all entries in the routing tables contain either the network address or the destination host.

The routing protocols are quite diverse, there are a large number of them, and each has its own merits and negative sides.